1. Field of the Invention
The present invention concerns a gateway between two data networks enabling a first network to access services in application servers on a second network. One application of the invention concerns an intelligent network. An intelligent network comprises a service network and a voice or data transport network.
2. Description of the Prior Art
The service network can have an object-oriented distributed architecture. One such architecture well known to the skilled person is the Common Object Request Broker Architecture (CORBA) of the Object Management Group (OMG). It comprises application servers, also known as service control points in the specialist terminology of intelligent networks. Services are installed on various application servers at various geographical locations, each server comprising a computer or a set of computers generally connected to at least one database. The following description uses both the term application server and the acronym SCP (Switching Control Point). In a CORBA architecture, the SCP is itself distributed.
Nodes of the transport network dialog with the application servers of the service network via a signaling network. The nodes of the transport network are in practise various systems able to handle a call, for example service access switches and intelligent peripherals. Intelligent peripherals are generally voice interface systems which can be added to the switches. The remainder of the description uses the acronym SSP (Switching Service Point) to designate the switch and the acronym IP (Intelligent Peripheral).
It is currently proposed that the communication protocol of the network nodes (on the signaling network) should be different from the communication protocol of the service network and therefore of the SCP. For example, the protocol for messages used by the service network is a protocol based on object requests, for example the CORBA protocol, while the protocol used for messages by the nodes of the transport network is an Intelligent Network Application Protocol (INAP), for example, defined by the Q.12xx series recommendations of the International Telecommunication Unionxe2x80x94Telecommunication standardization sector (ITU-T), and is not based on object requests at all.
A simple solution to this technical problem is to use a translation gateway to translate INAP messages from the nodes of the transport network and addressed to the application servers into messages understandable to the application servers, and vice versa.
A translation gateway of the above kind translates each message of the dialog between the various nodes of the transport network involved in a call of a given service (in other words, for a given service session) and an application server offering that service.
There are therefore as many messages at the gateway input as at the output.
An object of the invention is to reduce the number of messages exchanged with the service network to improve its performance by reducing congestion of the network, more particularly when the call to a service involves a plurality of nodes of the transport network, typically a service access switch (SSP) and an intelligent peripheral of that network.
In the current state of the art, a call on the intelligent network is received by an SSP of the transport network. If it is a call to a particular service, this is detected by the SSP switch which instigates a dialog with an application server SCP that offers that service (in other words, on which that service runs).
Some services, for example services involving authentication of the caller, require information that can only be obtained from an intelligent peripheral. The server SCP then requests the switch SSP to reroute the call to an intelligent peripheral and the latter instigates dialog with the SCP to obtain additional information. The intelligent peripheral can be a peripheral associated with the switch, i.e. directly accessible by the switch, or an intelligent peripheral associated with another switch of the transport network.
Thus the SCP has to manage two different dialogs for the same service call, a dialog with the SSP and a dialog with the intelligent peripheral.
The SCP can dialog directly with the intelligent peripheral if the communication protocol associated with the peripheral is the same as that of the SCP, i.e. the CORBA protocol, for example, or indirectly, via the gateway, if the protocol of the intelligent peripheral is different, and in particular follows the protocol of the SSP.
An object of the invention is to improve the performance of the service network in this intelligent architecture configuration in which a plurality of nodes of the transport network can be involved in the same service call.
The invention seeks to reduce the number of messages and to enable a better rate of re-use through improved modularity of the codes (programs).
The invention achieves this object in a gateway in which software processing usually executed on the data processing systems (application servers) on which the services are physically installed is distributed.
The gateway therefore comprises elements representing these services.
When it receives a call for a service transmitted by an SSP, the gateway associates an element representing the called service. This representative element provides software processing which includes monitoring the dialog with the SSP to collect all the information that the SSP can supply concerning the call.
In accordance with the invention, when the call is routed to an intelligent peripheral which sends a corresponding message to the gateway, the gateway associates that call from the peripheral with the representative element previously associated with the SSP.
In this way, a single representative element is used for the same service call involving a plurality of nodes of the transport network.
The invention therefore concerns a gateway between two data networks enabling a first network to access services in application servers of the second network, the first network comprising nodes susceptible of being involved in a call to a given service, the messages from at least one of the nodes of the first network conforming to a protocol different from the protocol of the messages from said application servers, which gateway:
comprises elements representative of services able to manage the various protocols,
associates a representative element for a dialog with a node of the first network for the call to a given service, and
associates the same representative element for a dialog with another node of the first network relating to the same service call.
According to the invention, the representative element controls the dialogs with the nodes of the first network for the service call to collect all the information it is necessary to transmit to an application server offering the service.
Control of the dialogs is effected autonomously by the representative element for at least a part of the dialog.
Also, the representative element composes messages by assembling information collected by means of the dialogs with the two nodes of the first network.
Finally, the representative element comprises a software process enabling a particular behavior to be adopted that corresponds to a request for specialization of the service or a sub-service which results from the information collected.